The databaseConneciton pooled has lower performance for directory connection? either less stable?

What this means? sounds impossible, under the jmeter/WAS tress testing, the tomcat with database/connection pooled has lower performance/response speed than no connection pooled, no metioned that the pooled system will become more unstable under the request extremly stress.

It seems impossible, for the pooled connection need no authentication anymore at runtime reference; now that the test is under the mysql database, I could change to oracle for further testing.

the test results for three host with different pools setting as below, tested by jmeter and WAS:

thread 10 in every second;
pooled
hits throughput average deviation
286 81/m 7343 2620
517 72/m 8296 3072
2633 81/m 7363 2630
331 69/m 8600 2995
348 48/m 109444 36123 (host2)
284 102/m 56626 23624 (host3)
nopool
257 94/m 6300 1963
433 81/m 7367 3211
278 79/m 6958 2101
352 86/m 6868 2149
205 97/m 24832 22582 (host2)
488 118/m 20608 28828 (host3)
thread 100 in every second;
pooled
hits throughput average deviation
726 64/m 91752 82118
745 69/m 84743 35246
1355 65 91785 36910
nopool
821 100.257/m 58161 16203
100 60/m 77346 20177
655 102 56400 14816
909 99.8/m 58692 20117

WAS pooled 10*5
10*5 9073.30 33723.22 No No
50*5 20076.09 22931.89 No No

WAS NO POOL
10*5 7457.49 30057.36 No No
50*5 19505.75 26290.35 No No
blogsite